Assaults on police stations killing seven, a chopped-up body discarded in rubbish bags, three execution-style murders and foreign tourists grazed by bullets: it's been a nasty week in the resort city of Acapulco, defying a much-flaunted crackdown on drug-related violence and delivering a serious blow to Mexico's tourism industry.

Drug wars killed more than 2,000 people last year in Mexico, and the state did little more than pick up the bodies.

President Felipe Calderón took office in December, and staked much of his political capital on showing the warring cartels that he is the boss with a massive security operation involving 25,000 troops and police.

"He didn't have much choice," said political commentator Jorge Zepeda. "The problem had got completely out of control."

But despite the roadblocks, air surveillance and boasts of intensive intelligence gathering - as well as the extradition of some important kingpins to the United States - the killing continues and there have been few arrests.

The 190 drug-related murders in January was a slight improvement on last year, but February could hardly have started worse. "We are going to persevere with this difficult and arduous battle requiring great sacrifice from Mexicans," Mr Calderón said this week. "But rest assured that we are going to win, and Mexico will be free."

The attacks on police stations in Acapulco were among the most spectacular so far in the bloody turf wars between the Gulf Cartel and the Sinaloa Federation - Mexico's main drug trafficking groups.

Dressed as soldiers and claiming to be carrying out a weapons inspection, the "commandos" first disarmed the police. They then opened fire while the massacre was recorded on video. Detectives later found a small arsenal of assault rifles, pistols, and grenades, in safe houses and getaway cars, along with military uniforms and a message reading, "We don't give a shit about the federal government".

It was bloody, brazen, and certainly not the news Acapulco's business leaders wanted to be discussing as the sun set over the resort's massive hotels, tacky beach discos, legendary cliff divers and luxury residences tucked away in exclusive coves beyond the main sweeping bay. Acapulco had already suffered shocking violence - evidence of which included a severed head washed up on the sand and two others stuck on poles outside a building last year. But the military operations were supposed to at least curb such violence.

Felix Salgado, Acapulco's mayor, regularly receives death threats and is protected by 12 bodyguards. "I hope this doesn't affect the tourist image," he said, adding that patrols "guarantee the safety of visitors".

But the patrols cannot guarantee safety. Last Saturday two Canadian tourists were grazed by bullets fired from a car on the city's coastal boulevard.

Militarisation

Tourism in Mexico employs 2 million workers and attracts around 20 million foreigners a year, including about 250,000 Britons. Numbers fell slightly last year partly, officials admit, because of the violence.

"The only answer is to militarise more," a source within the federal tourism ministry said. "But it gets to a point where the military presence itself scares people away."

Despite fears of human rights abuses as a result of the militarisation of domestic security, the operations have so far enjoyed cross-party support.

There is wide recognition in Mexico that most local civilian police forces are as likely to provide security for a drug lord's wedding party as bring him to justice, while the army is both far better trained and relatively clean.

The biggest risk, some analysts say, is that now they are exposed to the cartels on a regular basis more soldiers will follow in the footsteps of the Zetas - a hit squad formed from military deserters in the late 1990s.

"We could have the paramilitarisation of drug trafficking in Mexico," said a drug expert, Luís Astorga. "It would take the war to a whole other level."